Services like Gmail, Outlook.com and Yahoo! Mail block email to protect you from unwanted or malicious email such as phishing, scams, and spam. In this case they are mistaking email that you want for email that you don’t want.
If ask your email provider to unblock or whitelist an email address, email from that address will be more likely to get through. Here is an explanation of how to do that for Gmail.
Mark messages as "Not SPAM"
If Gmail has marked emails you wish to whitelist as spam, tell Gmail the emails are not spam.
- In Gmail, navigate to the spam folder.
- Search for emails containing the domain you wish to whitelist (eg onlinegroups.net).
- Select all the emails shown.
- Click More and then Not spam.
Check to see if address is being filtered
In the Gmail inbox, click on settings
Select the "Filters and Blocked Addresses" tab
In the "The following email addresses are blocked" section, make sure that your sending domain is not blocked. If it is, change it so that they are not.
Add the address to your contacts
Add the email address that is sending you email to your Gmail Contacts. Google will usually deliver email from addresses that are in your Contacts.
Go to Google Apps and select "Contacts"
Click on the "Add Contact" and enter the information for the contact to add.
Create a filter to tell Google to whitelist email from a domain
Click the cog icon in the top-right corner, and then Settings
- Click on Filters and then Create a new filter
- Enter the domain of the email you want to whitelist in the From field or
- Click Create filter with this search
- In the box headed When a message arrives that matches this search select Never send it to spam
- Click the Create filter button